The purpose of this research study is to evaluate the effectiveness and safety of a new treatment for achalasia of the lower esophageal sphincter. The esophagus is my food tube, and the muscle called a sphincter separates this tube from my stomach. Achalasia means that this sphincter muscle is too tight and fails to relax, so food does not pass properly into my stomach. As a result, I may experience difficulty swallowing, regurgitation, and weight loss. The new treatment being studies compares two different doses of botulinum toxin type A (Bo Tox(R)) to keep the sphincter open. This procedure involves injecting Bo Tox(R) into the sphincter muscle to open it. This procedure has been studied by Dr. Pasricha in patients with achalasia, in which Bo Tox(R) 80 units was injected into their esophageal sphincter during an endoscopy. After six months, 65% of the patients had experienced relief and still did not have their achalasia symptoms. After 1 year, 424 of the patients did not have symptoms. It is thought that using Bo Tox(R) will provide a safer and easier alternative to the current treatments. The current treatments for achalasia include balloon dilation (widening) of the esophageal sphincter, or surgery. This study will also determine whether using Bo Tox(R) in higher doses will cause toxicity (overdose), and will relieve the symptoms of achalasia for longer time periods. Botulinum toxin type A (Bo Tox(R)) is a product cultured from Clostridium botulinum, a toxin which when found in nature is known to be poisonous, and causes muscle paralysis. However, this preparation has been specially prepared for use as a medicine, and is commonly used to treat patients who have eye problems, such as droopy eyelids, for which has FDA approval. The use of Bo Tox(R) is not approved by the Food and Drug Administration (FDA) for use in achalasia, but it is used to treat this condition at some medical centers.